The teams travel to France and Italy on Sunday
Leinster and Connacht were the only Irish teams to win last weekend.
While Leinster earned a bonus point win over Castres in a 33-15 win, Connacht earned a famous win at home to Toulouse. Both teams are on the road this weekend, with Leinster travelling to France, while Connacht meet their Pro12 rivals Zebre.
Leinster's European record in France in recent years is not good ahead of their game with Montpellier. In their last nine trips to France, the team have beaten Castres twice and Racing Metro in January 2011.
Not including those two Castres games, the Racing win happened seven games ago. Leo Cullen's side will need to be on top form this weekend against Les Cistes, which now boast Munster scrum-half Tomas O'Leary in their ranks as a "medical joker".
While Joey Carbery impressed last weekend in place of Johnny Sexton, this weekend sees Sexton return to the side, in an atmosphere that will be different from the one in the RDS.
Ireland and Lions flanker Sean O'Brien will also be reintroduced into the set-up, having not played for the province since last January.
A view of the Lanfranchi Stadium as September's game was abandoned. Mandatory Credit ©INPHO/Matteo Ciambelli
Connacht travel to Parma, for the second time this season, and will hope it's their first game that concludes. In September their Pro12 game was abandoned at half-time due to weather conditions when the home team were winning 22-10.
Such has been the progress of Connacht in recent years, head coach Pat Lam rued missing out on the bonus point in their home win over Toulouse. A bonus point win on Sunday in imperative if the team are to try and reach the knockout stages of the tournament for the first time ever.
Last weekend, Wasps recorded an 82-14 win over the Italians, which will have done Connacht no favours ahead of the game. It also served as a reminder of what awaits from the Coventry side, in the back-to-back fixtures in December.
The team are going into the game off the back of three straight wins. South African fly-half Marnitz Boshoff arrives in Galway this week, which will give the team a much-needed boost in a sombre week for the sport in Ireland.
Both Leinster and Connacht will be hopeful on winning this weekend, Two wins from two matches will set up both for a run at the quarter-finals. After no Irish teams reached the last-eight last season, that would be massively welcomed.